Iron is completely different from bronze and other copper alloys both in the way it's smelted and the way it's worked, and so it represents a major technological shift.
Firstly, when working at copper-smelting temperatures, although the iron will reduce from its ore it doesn't melt but instead forms a spongy mass called a bloom, which looks pretty grotty when brought out of the furnace. This then has to be re-heated and beaten to remove intermixed slag and consolidate it before you get to the point of being ready to turn it into something. You need to heat and shape the billet of metal into what you want, and its malleability decreases rapidly once it's below red heat. This is in complete contrast to a copper alloy, where you can put your ore in a crucible, smelt it and pour it straight into a mould, and in the case of a lot of copper alloys, doesn't respond very well to being beaten whilst hot
Joining is also completely different, iron needs to be heated to near-white heat and the pieces quickly hammered together to effect a weld, something you can't do with bronze. You can do this with pure gold at room temperature but that's a different story!
As for hardness, pure iron is actually softer than bronze, especially bronze that has been work-hardened (i.e. cold-hammered). Iron with up to about 1% of phosphorus in it can be work-hardened to gain a similar hardness to bronze, but realistically iron only gains an advantage over bronze when it a) contains between about 0.3 and 1.2% of carbon b) has been extremely rapidly cooled from red heat, and c) has been partly re-heated to within a fairly narrow temperature range. In other words, you need steel, and to know how to quench and temper it to gain a big advantage over bronze but once you have this technology, you have the means to produce tools and weapons that are both harder and more shock-resistant than any copper alloy.
We know that in antiquity people did manage to work all these things out, most likely in Anatolia roughly 3,500 years ago. Obviously, everything won't have happened all in one go, there would have been a few hundred years of trial and error before you get to the point where there is a viable iron industry, but we do know that the Hittite civilisation seems to have been the first one to get ironworking to the point where it gave them a big advantage over their neighbours.
Iron does have one really big advantage over all of the copper alloys, which ultimately put it in the dominant position and that's availability of the ore. Copper is relatively scarce and thus expensive, tin even more so, but iron ores are easily available. So, ironworking slowly made metal more available to ordinary populace as it was something that could be made from reasonably local resources, as opposed to expensive imported bronze.
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